Goodwill and Other Intangible Assets (Aggregate Amortization Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	$ 20,844	$ 22,050	$ 22,417
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	17,132	18,566	19,442
Credit Card and Trust Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	2,883	2,682	1,975
Merchant Processing Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	$ 829	$ 802	$ 1,000